Feature #200

Add Have the possibility to choose which results are exported reduce the size of the binary corpus to the minimum necessary size (for example, by deleting some directories like interp, ptokenized, tokenized, treetagger, wtc). This parameter could be set through the parameters interface (tools/parameters/txm/user/export). The default value could be "light" ? (the advantage of choosing the "complete" option should be explaned, anyway).